The present invention relates to an electrothermal firing device including a breechblock and a tube provided with a charge chamber and a projectile path portion or barrel, and wherein first and second electrodes, which are separated from one another by a sleeve of an electrically insulating material, are disposed in the charge chamber at the respective ends thereof. The invention further relates to a cartouche or cartridge for use in such electrothermal firing devices.
Electrothermal firing devices are disclosed, for example, in Unexamined Published German Patent Applications DE 3,613,259.A1 and DE 3,816,300.A1. A significant component of such devices is the combustion chamber (charge chamber) in which, with the aid of an electric arc of a high arc voltage (e.g., 30 kV) through which flows a high current (e.g., 400 kA), suitable substances are heated and converted to the gaseous state (plasma). Pressures up to 1 GPa are generated thereby. Finally, the gases under these high pressures are employed to accelerate projectiles in a tubular weapon.
In the prior art electrothermal firing devices, two axially displaced electrodes are disposed in the charge chamber, with the first electrode being brought coaxially through the breechblock of the firing device and being configured as a high voltage electrode. The second electrode is disposed adjacent the projectile and is connected to ground. Such an electrode arrangement permits easy contacting with the grounded tube or barrel of the weapon in the region of the second electrode, while the first high voltage electrode, which is under considerably more mechanical stress, must be supported in an extremely expensive manner. The reason for this is that the first electrode is wrapped in insulating material to insulate it against the breechblock and the generated forces must be supported by this insulating material. Moreover, loading the projectile and a cartouche or cartridge including the electrodes into the firing devices is difficult since the high voltage electrode must be brought through the breechblock. Thus, the breechblocks of conventional guns cannot be employed with the prior art electrothermal firing devices.